Mn3O4-coated activated carbon (Mn3O4/AC) was prepared by supercritical technique and applied for the
removal of Pb and Cu ions from aqueous solution. Kinetic and isotherm data of the adsorption by Mn3O4/
AC were compared with those of activated carbon (AC) and pure Mn3O4. Adsorption of metals was
adequately described by pseudo-second-order kinetics and Langmuir isotherm models. Maximum
adsorption capacities of Pb and Cu ions determined by Langmuir modelwere enhanced 2.2 and 6.1 times
for Pb and Cu ions by Mn3O4 coating onto AC, which might be attributed to reduced resistance of
intraparticle diffusion and enhanced surface electrostatic interaction and complexation by Mn3O4.